The present invention relates to a laminate of metal plates such as a rotor core or a stator core for a rotating electrical machine such as a motor and to a laminating method for the laminate.
Typically, a core for a rotating electrical machine is a laminate of metal plates. The core is configured by joining a plurality of laminated core plates together. Structures for joining such laminated core plates are disclosed in Japanese Laid-Open Patent Publications No. 2-264411 and No. 2006-166500. Specifically, the structures join the laminated core plates to one another by engaging a projection of each of the core plates with a recess or a hole formed in an adjacent one of the core plates in the laminating direction.
However, since the conventional structures join the core plates simply through engagement between projections and corresponding recesses or holes, a high joint strength cannot be ensured. To solve this problem, an additional component must be employed to fix the laminated core plates together, thus complicating the structures. Further, if projections and recesses, each having a triangular cross section, are employed, the projections may be displaced along the inclined wall surfaces of the triangular recesses unless the positions of adjacent core plates are properly determined. As a result, a gap may be easily formed between adjacent core plates. This hampers the core function.